EFLOW EF-Series - Built-In Discrete Output

EF-Series Instruction Manual
Rev 2/01 2-11
The host port can receive messages in ROC protocol and will respond in kind. The host port is capable
of initiating a message in support of Report by Exception (RBX) and Store and Forward when using
ROC protocol. Refer to the ROCLINK Configuration Software User Manual.
For installations using radio communications, battery power can be conserved by cycling power to the
radio or cellular telephone. The power cycling control is achieved through the EIA-232 communica-
tions card. The radio or cell phone is connected to terminals located on the EIA-232 communications
card, as described in Section 3. For configuration, refer to the Radio Power Control function in the
ROCLINK Software User Manual.
The communications connectors on the Main Electronics Board provide the EF-Series unit with
electrical access and mounting provisions for the optional communications cards. The
communications card mounts directly on the connectors at P3 on the Main Electronics Board and is
held in place with three compression stand-offs. The stand-offs on the Main Electronics Board pass
through the communications card. The communications cards available for the EF-Series unit allow
the options of serial data communication and modem communications. Refer to Section 3.
2.4.5 Built-In Discrete Output
The EF-Series unit provides a discrete output (DO) to provide control capabilities for a sampler or
odorizer. The discrete output is capable of switching up to 0.3 amp of current. Refer to Table 2-2.
Table 2-2. Discrete Output
Output voltage during ON state Battery voltage - 0.7 volts
Output voltage during OFF state 0 volts
Output Current 0.3 amp maximum
Maximum voltage 22 volts maximum - clamping occurs
The built-in discrete output on the EF-Series unit is intended to perform sampler functions, but may be
used as a standard DO. This includes toggle mode, latched mode, and timed DO mode. The discrete
output is accessed by the configuration software as DO Point A4.
When the Sampler function is enabled, the EF-Series unit provides a time duration output (TDO) based
on the volume. A control volume and a pulse duration must be specified with the Sampler function.
After each flow calculation, an internal volume accumulator is compared to the control volume. If the
accumulator exceeds the control volume, a pulse is output and the accumulator is reduced by the
control volume. This output may be used to drive an external totalizer, odorizer, gas sampler, or
similar device.