Chapter 6 Additive Control; Overview; Piston Injector Cycles - Toptech Systems MultiLoad II User Manual

Chapter 6 – Additive Control
CHAPTER 6
6.1 O
VERVIEW
Sophisticated additive control is an integral part of the MultiLoad II. Because this control is integrated into the
MultiLoad II, the need for discrete additive control devices and their resulting interfaces to the terminal automation
system have been eliminated. Up to 16 injectors (2 injectors on SMP) can be assigned to a load arm on
MultiLoad II.
Additive injection rates are entered into the MultiLoad II as a percentage of the total product recipe. For example,
if the additive injection rate is 0.5000 gallons of additive per 1,000 gallons of product, the percentage of additive in
the product recipe would be 0.0500%. Once this number is established, any injection size (Additive Volume Per
Injection) can be programmed in the MultiLoad II as long as it falls within the mechanical limitations of the injector.
MultiLoad II adjusts the frequency of injections to maintain the correct additive percentage.
This chapter describes the MultiLoad II Additive functions and features. Please review the topics that describe
characteristics that are generic to all additive methods before studying the individual methods. The five additive
methods discussed in this chapter are:
- Piston Only (calibrated cylinder)
- Piston with Input (calibrated cylinder with feedback switch)
- Solenoid & Pulser Input (additive meter only)
- Common Meter for Multiple Additives
- Analog valve/pump using PID loop control
This chapter also describes the Additive Calibration features available with the MultiLoad II.
6.2 P I
ISTON NJECTOR
The Piston Throw Time is a parameter that is configured for all of the piston type methods. The Throw Time is
the max time it takes the piston to complete one half cycle. Note this is not a calculated value, but is determined
by physically measuring the time it takes the piston to complete one half of a cycle.
When an injection is initiated, the system will assume that the piston has traveled to its maximum extension point
when the Throw Time has expired. After the Throw Time has expired, the injection signal is removed and the
piston begins its return to the starting position. The time that it takes for the piston to return is assumed to be
equal to the piston Throw Time also. The system will not attempt another injection until the return Throw Time
has expired. The piston must return to the starting position within this time period. Please refer to Figure 6.1
below.
Firmware Version 3/4.31.37
A C
DDITIVE ONTROL
Toptech recommends the Solenoid & Pulser Input method because it
provides all additive control totalizers and calibration in a very
straightforward manner. This method also eliminates the need for any
microprocessor-based additive injection equipment, saving considerable
expense in additive system training and maintenance.
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