PART TWO - INSTALLATION
SECTION 3 - ELECTRICAL CONNECTIONS
Rev. 6-501
Model P53 pH/ORP Analyzer (universal-mount 1/2 DIN)
29
3.6 Closed Contact
TTL Input
☞
The analyzer TTL input feature enables you to conveniently
hold or transfer analog outputs and CONTROL and ALARM
relays. How the TTL input feature functions depends on
what output state (HOLD, XFER or ACTIVE) was selected
during the last calibration:
•
If HOLD was selected, the TTL input will hold analog
outputs at their last measured values, and hold relays
in their present “on/off” states.
•
If XFER (transfer) was selected, the TTL input will
transfer analog outputs to their user-entered preset
values, and transfer relays to their user-entered preset
“on/off’ states.
•
If ACTIVE was selected, the TTL input becomes dis-
abled, keeping the outputs and relays active so they
can respond to the measured value.
To apply a TTL hold or transfer, either locally or remotely
connect TTL Terminal 9 to Terminal 10 on TB1. When this
input is broken, the applied hold or transfer releases.
NOTE:
The TTL input feature can be affected by three
other methods used to hold the analog outputs and
relays, which are listed in order of precedence:
1.
Selected Calibration Output State:
The out-
put state (HOLD, XFER or ACTIVE) selected
during a calibration always takes precedence
over the TTL input. If the TTL input was oper-
ating, it will be re-applied after calibration (or
aborted calibration) and will function according
to the last selected output state.
2.
TEST/MAINT Menu HOLD OUTPUTS Func-
tion:
The TEST/MAINT hold always takes
precedence over the TTL input. If the TTL input
was operating, it will be re-applied after the
TEST/MAINT hold is released.
3.
Active TIMER Relay:
An applied TTL input al-
ways takes precedence over a TIMER relay.
When the TTL input is applied, it suspends the
TIMER relay countdown until the TTL input is
released. Thereafter, the TIMER relay resumes
its countdown from the point where it was sus-
pended.
