Next Advance SP2200 - Manual (Page 42)

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SP2200Programmable Syringe
Pump
Publication #1200-02 37 04/29/10
9. Logic Interface: TTL Input and Output
Expansion Connector Pin Out
Ground Ground
Pin 1 (LSB) Ground
Pin 2 Ground
Pin 3 Ground
Pin 4 Ground
Pin 5 (MSB) Ground
VDD n/c
Figure 1: Rear of Pump
On the PCB on the bottom of the pump is a DB-9 connector, labeled ‘TTL I/O’, which is used for TTL I/O.
The logic signals on this connector permit bi-directional control with external equipment.
In addition, an Expansion Connector is available with 5 TTL lines for additional functions. To use the
expansion connector, the PCB needs to be modified as indicated in the diagram above. Header pins can be
soldered to the PCB to attach a cable.
Control input TTL logic levels must be held steady for a minimum of 100 ms to be recognized. To minimize
the possibility of false signals caused by glitches and ringing, which could be caused by the closure of
mechanical switches, TTL control inputs are software filtered. With a sampling period of 50 ms, glitches of
less then 100 ms are filtered out.
Edge detection requires the detection of a change in TTL levels. With a minimum of 100 ms to detect a level,
an edge requires a minimum of 200 ms to be detected. Since the next level change can be detected in 100 ms,
creating another edge, the maximum edge to edge frequency is 10 Hz.
Edge changes to the ‘Pumping Direction’ and ‘Operational Trigger’ inputs must occur at least 50 ms apart.
Falling edge refers to a logic high to logic low transition. Rising edge refers to a logic low to a logic high
transition. To guarantee recognition of logic levels, voltages on the input lines must be within the following
ranges:
TTL logic low (0): 0 to 1.5 V
logic high (1): 3.5 to 5.25 V
The Vcc and Ground pins, pins 1 and 9, are for logic reference only. To assure proper voltage levels, the
Ground pin should always be connected to the signal ground of a sensing or controlling device that is attached
to any other pin on the TTL I/O connector. The Vcc pin should not be used to source current. The TTL I/O
pins are defined as follows:
Expansion
Connector (See
Pin Out)
Pin 5
RS-232
Pump
Network Computer
Pin 1
TTL
I / O
Power
Connector
JP3 JP1
Resistor pads, or solder 2 pads if none.
Suggested resistor value is 200 Ω.
Motor
Connector
DB-9
Connector