Despatch P1400+ Temperature Controller User Manual

Page 16

SECTION 4: WIRING INSTRUCTIONS

Electrical noise is a phenomenon typical of industrial environments. As with any instrumentation,
these guidelines should be followed to minimize the effect of noise.

4.1 Installation Considerations

Ignition transformers, arc welders, mechanical contact relays and solenoids are all common sources
of electrical noise in an industrial environment and therefore the following guidelines MUST be
followed.

1. If the instrument is being installed in existing equipment, the wiring in the area should be

checked to ensure that good wiring practices have been followed.

2. Noise-generating devices such as those listed should be mounted in a separate enclosure. If

this is not possible, separate them from the instrument, by the largest distance possible.

3. If possible, eliminate mechanical contact relays and replace with solid-state relays. If a

mechanical relay being powered by an output of this instrument cannot be replaced, a solid-

state relay can be used to isolate the instrument.

4. A separate isolation transformer to feed only the instrumentation should be considered. The

transformer can isolate the instrument from noise found on the AC power input.

4.2 AC Power Wiring - Neutral (for 100 to 240V AC versions)

It is good practice to ensure that the AC neutral is at or near ground (earth) potential. A proper
neutral will help ensure maximum performance from the instrument.

4.3 Wire Isolation

Four voltage levels of input and output wiring may be used with the unit:

1. Analogue input or output (for example thermocouple, RTD, VDC, mVDC or mADC)

2. Relays & Triac outputs

3. SSR Driver outputs

4. AC power