Interface between honeywell TDC3000 and FACP


Thread Starter


I am involved in installing FACP in industrial complex where the DCS is Honeywell TDC3000. The FACP must make all messeges available to TDC3000 for reading. I want to use a MODBUS protocol to do that.

1- where do i start????
2- What do I need????
3- how can I test the communication off site to make sure it is working before installation???

Ruediger Trobisch


I do not know what FACP mean, but as I know, the only way to connect to a TDC 3000 is via the PM/(A)PM serial interface option. So you need the interface, cabling and a FTA.

Christopher L Crowley

The Honeywell TDC can communicate Modbus using the PLCG, EPLCG or the HPM Serial Interface.
Thank you for your response FACP is (Fire Alarm Control Panel)the requirment is to make through MODBUS Protocol data collected by FACP available to TDC3000 for control purposes.

Thank you again.
Thank you for your response.

Are we talking here about cabling problem only (am i making big Q of small issue)? i will not be touching the TDC. only I have to make data collected by the FACP available in accessable form for the TDC. work on the TDC will be done by honywell integrator.
Several issues to concern yourself about.

1. Cabling and data highway.
If your FACP is further then 50 feet maximum length that RS-232 can communicate you will have to convert to a RS485/422 data highway. There are many converters available to do this. The RS485/RS422 network will require a two pair shielded cable 22 or 24 AWG communication cable.
If FACP is within 50 feet then all you will need is a three conductor cable 22 or 24 AWG shielded for Tx, Rx, and Com.

2. Connection Pin out for RS-232 at both ends.
You will need to cross the RX to TX from the TDC-3000 to the FACP. Connectors are usually 9 or 25 pin D-Sub.

3. Communication Settings
Both the DCS and FACP will need to be configured
for Baud rate (usually 9600 or 19200), Communication Mode - Modbus RTU or ASCII (usually Modbus RTU), Parity (Odd, Even, or None), Bit size (usually 8), and stop bit.
Your FACP I assume is the slave so it will need a Modbus slave ID number (usually default is 1)

4. the hard part a Modbus Map
You need to know each type of signal you want to communicate type, digital or analog (integer, floating point etc.), whether to read or write to slave. I suggest get with your DCS programmer for this and get your manual out on your FACP. The FACP may have a set Modbus Map that your DCS may read. Suggest you go to Modbus site and read up on programming to understand mapping.

Hope this helps
On the cabling distance issue, the APM serial interface can communicate at distances up to 300 meters by putting the Serial Interface FTA card at the device (FACP), and using a long cable run for the Power Adapter to FTA with 4 conductor cable. That way, RS232 can be used. We use this configuration with Allen Bradley, Triconex, Bently Nevada and PC modbus links.

- John