Dynasonics TFXM Series Ultrasonic Multi-Channel Flow Meter User Manual download pdf (Page 15)

Rev. 8/02 -1.14- TFXM

Max Loop Load = (External Supply Voltage - 5)

0.02

Cable used to transmit 4-20 mA signals should be routed in wiring

trays or conduits that carry instrumentation signals. It should not

be run with AC power or other potential sources of noise. Very

long cables can be accommodated, but the resistance of the wire

must be added to the total loop load to ensure that adequate

power is available to power the load. Shielding of the wires carry-

ing 4-20mA signals are typically not necessary, but is recom-

mended when wires must be run past or in proximity of electrically

noisy circuits.

Two independent SPDT (single-pole, double-throw, Form C)

relays are integrated into the TFXM for each measuring channel

installed within the flow meter enclosure. The relay operations are

user configured via software to act in a flow rate alarm, signal

strength alarm or totalizer/batching mode. See Figure 1.4 for ter-

minal block locations. The relays are rated for 200 Vac max. and

have a current rating of 0.5 A resistive load [175 Vdc @ 0.25 A

resistive]. It is highly recommended that a slave relay be utilized

whenever the control relays are used to control inductive loads

such as solenoids and motors.

An RS485 driver and Modbus protocol is utilized by the TFXM to

communicate between the two channels located within the TFXM

flow meter enclosure (if so equipped), communicate with satellite

TFX flow meters and to interface with a personal computer sys-

tem. The TFXM can be used as the Primary meter (Master) to

program other Secondary (Slave) meters located on the RS485

network. The TFXM contains a feature that permits up to 8 flow

measurement channels to be mathematically manipulated. Soft-

ware configuration is covered in Section 4 of this manual.

RS485 interconnections are made at the terminal block located

within the TFXM Field Wiring Access Panel. See Figure 1.4. Util-

ize two conductor plus shield wiring cable for this purpose. Avoid

running these cables in wiring trays or conduits carrying AC power

or other electrically noisy devices.

PART 1 - INPUT/OUTPUT CONFIGURATION

Control

Relays

Configuration

RS485

Configuration

1 2 ... 10 11 12 13 14 15 16 17 18 19 20 ... 106 107

No comments

Dynasonics TFXM Series Ultrasonic Multi-Channel Flow Meter User Manual Page 15