from the Forum department...Mobus slave Address
About modbus protocol
I don't know what 248 to 255 are used for. They're not used because that's what the Modbus spec...
from the Design department...RS232C to MODBUS Interface
Request for help related to appropriate hardware-software interface
It isn't a Modbus master you're looking for, it's some other set of functions relating to what...
from the Forum department...Why 250mA fuse for 4-20mA analog input?
Why 250mA fuse for 4-20mA analog input?
I suspect that a fuse installed in a 4-20mA loop is an attempt to protect an analog input on a 2...
from the Forum department...Modbus Register read
Howto read Modbus registers to a HMI
My recommendation is to use a generic Modbus master, like Win-Tech's Modscan32 in order to be able...
from the Forum department...Network control of 4-20ma output
Network control of 4-20ma output
I've used the WebRelay, and the people who make it have a catalog of control-via-web stuff. But...
A colleague used a Red Lion Data Station Plus (DIN rail mount control module with serial and...
from the Dept of Bento Boxing department...ModBus Plus
4-5 years ago I stopped by the Modbus booth at the national ISA show. I told the booth guy that...
from the Forum department...terminating resistor
This 7 minute video on youtube, Reflected waves on a cable, shows the distorted waveform on an...
from the Spare materials needed department...Looking for source of manual control units
Our process control systems are run by PLCs and have manual backup panel mounted in the control room. The OEM has gone to a semi- computerized MBU.
I've heard that the US nuclear power industry is served by some companies that reverse engineer and...
from the Forum department...Turbine flowmeter error
Turbine flowmeter reading much more than should be
> maybe there was something wrong with the mechanical transmission between the turbine and the...
from the Automation List department...MicroLogix RTD cards
Measurement errors in Allen Bradley MicroLogix RTD cards
I've had to 'calibrate' one PAC controller (not an AB uLgx) at its working temperature in its very...
from the Forum department...RTD
RTD PT110 and PT10 connection to DCS RTD Module in Yokogawa Centum VP.
If your existing analog input module does not support either - your types of RTDs, or - generic...
from the Forum department...Temperature compensation for level sensing technique
Temperature compensation for density variation of air in hydrostatic measurement
FYI, a year ago, maybe two years ago, a forum topic involved diminishing air pressure in a closed...
from the KID department...MODBUS Address
MODBUS Address - how to identify?
The Modbus Standard Modbus over Serial Line V1.02 (downloadable for free at Modbus.org) says: ...
from the Student KaHo Sint-Lieven Gent, Belgium department...Modbus RTU NO_RESPONSE
Slave Device does not respond to the master.
2 wire RS-485 is implemented differently from manufacturer to manufacturer. Although you might...
from the Forum department...Problem with energy meter using Modscan
Problem with energy meter using modscan
1) Have you tried looking at more than one data format? 2) Have you tried reading from another...
from the modbus department...Proview - modbus - plc
Proview - modbus - plc
The link below is to a Chipkin's "Modbus for Field Technicians" document that covers...
from the Instrumentation department...Flange type DP Transmitter zero error
Flange type DP Transmitter zero error
What is the "top side" connection"? dry leg? wet leg? capillary with a diaphragm...
from the instrumentation department...Instrumentation Books
Can you recommend a book about instrumentation and process control in a petrochemical plant and oil and gas
A frequent control.com contributor, Walt Boyes, is author of an excellent instrumentation book,...
from the Instrumentation department...generating Hook-Up drawings for field instruments
Material For preparing Hook up drawings
You can read Liptak's comment on loop diagrams for smart instruments here: ...
Key term: Instrument Loop Diagram ...
from the Forum department...Bearing Temperatures
Bearing Temperatures hunting
Installing Instrumentation on Insulated Bearings ...
from the Instrumentation Engineering department...Is there any difference in signal transmitted in HART and Fieldbus or not?
Is there any difference in signal transmitted in HART and Fieldbus or not?
from the Forum department...T/C extension wires
use of neutral extension wires in industrial temperature measurement
Curt, Those L&N's you remember are probably not that much different from the one on display...
Neutral extension leads (as described in "Temperature Measurement", 1999, CRC Press)...
I hope not many, but I have seen it. If by "neutral extension wires" you mean that...
from the Modbus links department...modbus reading not actual
Not getting real values and rapid changing Modbus reading from Allen Bradly PLC
The data in the slave/server (presumably data in the PLC?) is in a format that has to be...
For example, what reading do you expect? As examples, what readings are you getting that do appear...
from the Siemens PLC department...Adding Pyrometers to an assembly line
Incorporating Pyrometers into an assembly line
I guess it depends on the complexity of the pyrometer and what the intention is. Is the...
from the I & C department...Rosemount Level transmitter Trouble
Why are my Rosemount 3100 Level transmitter readings seem wrong (Lower than expected) even when my tank level is high?
If the readings are always low, then the reference level point and the bottom level points are...
from the Instrumentation department...Does the reading of a differential pressure transmitter change if we use a capillary tube?
will the reading of a differential pressure transmitter change if we use a capillary tube?
It depends on whether you have one remote seal on an open tank or two remote seals on a closed tank....
If you have two remote seals, one at the bottom with another one at the top, then you can move the...
Theoretically, the fluid in the capillary should transmit the pressure the same as tubing. But...
from the Forum department...Minimum voltage for Hart communication
Need you opinion on this topic: Minimum voltage for Hart communication
It's Ohms Law. To drive the same current through greater resistance requires a higher voltage: ...
The vendor assertions about minimum voltage are indeed correct. What you've missed is the minimum...
from the Obsolete Meters department...Digital Panel Meters
Suggestions for Obsolete panel meter replacement
In the US, those are known as 1/8 DIN panel meters which designed to fit in the same panel cutout...
from the Automation List department...Flow totalizing from analog input
On a system consisting of a SLC 5/04 and a Panel View 1000, we want to display a running total from Signet Flow transmitters...
Just because the previous posts are a decade old, does not invalidate them. Same situation today...
from the Forum department...Thermocouple and DCS Readings Different, possible cause?
Possible issue with WX compensation cable to DCS reading of Thermocouple temperature?
A 5°C error (maybe greater) is possible with some handheld digital thermocouple thermometers...
from the Forum department...Trouble Communicating with Micro Motion Liquid Density Meter
I could not communicate with my PC when i connected the MM LDM 7835 to my PC
Assuming your software actually talks through a serial port, you need to check - Windows'...
from the Instrumentation department...Motorized control valves
How does a motorised control valve works?
It's not a problem if one is clairvoyant, but I'm not. Some MOV's use 4-20mA input. Some...
A major American manufacturer or two cannot provide wiring diagrams without the device's serial...
from the Forum department...compensation cable in tc
about compensation cable info reqirements
Thermocouple extension cable is required because it completes the measurement, which is the EMF...
from the Automation List department...Honeywell S9000 serial communication
Pin Configuration for 25 pin RS232/RS 485 pin
If the information is available anywhere, it's probably in the S9000 Communications reference...
from the INSTRUMENTAION department...HART Communicator does not connect with transmitter
When using HART COMMUNICATOR to interrogate the transmitter while carrying out PM or CM, HART COMMUNICATOR displays "NO COMMUNICATION".
Four things are needed for HART communication: 1) a HART enabled transmitter 2) a DC power...
from the Instrumentation department...Wrong Thermocouple Extention Cable
What is the error if you use a Tx cable with a K thermocouple?
Just how much extension wire that needs to be replaced is involved here? A couple hundred feet?...
Oops, I stand corrected. In my earlier post, I was thinking ordinary copper wire was the...
Here's my rationale on the topic: I don't think the error is a linearity question related to...
from the Forum department...Extended Modbus
Explanation for extended modbus
The question is about 5 bit (4xxxx) or 6 bit (4xxxxx) addressing. One earlier thread (Aug 27,...
from the Forum department...Range of Pressure Transmitter
Range of Pressure Transmitters
Everything effects 'accuracy'. Everything like temperature, aging, line pressure, hysteresis. So,...
from the Engineering department...Wireless TCP/IP Transmitter / Receiver Combination
What is the best way to connect Modbus TCP/IP wirelessly to a Siemens building management system or SCADA system?
A modem converts one communications medium to another, like in the old days, a PC's binary RS-232...
There has been an alarming increase in the number of things you know